Discharge assembly for centrifugal separators



" Nov. 13, 1951 DISCHARGE ASSEMBLY FOR CENTRIF'UGAL SEPARATORS J. E. COOK Filed Sept. 2, 1948 III BY JqMEsE. 000K 7 Patented Nov. 13, 1951 UNITED STATES PATENT OFFICE DISCHARGE ASSEMBLY FOR CENTRIFUGAL SEPARATORS Application September 2, 1948, Serial No. 47,358

2 Claims. (01. 233-21) This, invention relates to centrifuges and particularly to centrifugal separators of the type in which at least one of the separated components of the mixture is maintained out of contact with atmosphere during its passage frnm the centrifugal bowl to a stationary discharge pipe.

In. centrifugal of the so-called closed type, as disclosed, for example, in Lindgren Patent No. 2,002,954, the separated components from the chamber of the centrifugal bowl are discharged through, separate outlets in the bowl neck which is closely surrounded by flexible and elastic tightening devices or seals. The latter are arranged to accommodate radial vibrations of the neck incident toits rotation, while maintaining separate air-tight communication from each outlet of the neck to a stationary outlet pipe or duct. Centrifuges of this type are in extensive commercial use because of the recognized advantages in thu xcluding air from he epar ted c p nents of certain products.

It is now common practice to provide in one of the stationary discharge pipes of such centrifuges an adjustable yielding resistance to outflow of the separated component, so that by adjusting the resistance, it is possible to regulate the concentration of one of the separated components, for example, the fat content ofcream separated from whole milk. A closed centrifuge so equipped is disclosed in Hapgood Patent No. 2,160,140. As there shown, the separated cream or other lighter component discharges through the top of the rotating bowl neck which opens into a stationary receiving chamber in, a, block removably secured to the. centrifuge frame. by a put. The block also assists in holding flexible seals in place around the bowl neck between the cream. and skim milk outlets. From the stationary receiving chamber, the cream passesupwardly into. a vertical cylinder through a yielding resistance in the form of a spring-loaded disc; valve, the loading of which can be adjusted. The valve is guided in its vertical movements by a stem slidable at its lower end in a, centrally depressed portion of a valve seat forming the bottom of the cylinder. At its upper end, the stem is connected to a diaphragm mounted in the upper end of the cylinder and serving to counteract the effect on the valve of cha ges the ack-pres ren he r a dis: charge. l ne extend ng. latera ly from. the intermediate port cn of the cylind The. cy de an he valve. seat ar remova ly secur d to th und rlyi g: lock by a e nd. nut.

Separators, oi the closed type provided with a valved discharge, as; described, have substantial operating advantages over prior separators of this type and consequently are used extensively. However, the discharge assembly is somewhat complicated because of the number of parts which heretofore have been regarded as necessary; and the arrangement of these parts materially increases the over-all height of the separator. Moreover, cleanin of the assembly is somewhat complicated by reason of the number and arrangement of the parts and the multiple nuts for holding them together.

The present invention, therefore, has for itsv primary object an improvement of the abovedescribed discharge assembly for closed centrifuges, whereby the number of parts and the over-all height are reduced, and the parts may be more readily disassembled and cleaned.

A separator made in accordance with the present invention comprises a stationary block seated on the seat surrounding the bowl neck and having in its, lower portion a recess forming a receiving chamber for liquid discharged from the bowl through the outlet in its neck. At its upper portion, the block has an integral flange forming a wall of the receiving chamber and defining a valve orifice through which the discharged liquid passes from the receiving chamber into a vertical cylinder or hollow member. The valve orifice in the block is considerably smaller in diameter than the recess forming the receiving chamber, so that the orifice provides a restricted flow path for the liquid. The cylinder contains a disc valve adapted to seat on the block flange to close the orifice. Guiding of the valve is effected entirely lateral projections slidably engaging the inner wall of the cylinder. The spaces between these projections allow flow of the liquid up through the cylinder from the valve orifice when the disc valve is unseated. The latter is provided with suitablev means for biasing it toward its closed position, thus imposing a yielding resistance to the flow of liquid into the cylinder.

The block is held in assembled relation to the underlying centrifuge frame and the overlying cylinder by means of a fastening element which, however, is. spaced from the block. More particularly, the fastening element spans the block and, at its lower end, is threaded or otherwise releasably connected, to the frame. The upper edge or the fastening element has a holding portion,

overlying an interrupted shoulder on the cylinder, and also has a diametrically opposed locking per--v tron normally overlying the shoulder but adapted,

upon; rotation of the fastening element. to register with the interruption in the shoulder. In the latter position, the cylinder can be tilted without interference from the locking portion, and is then movable laterally to disengage the holding portion and remove the cylinder for cleaning or any other purpose. However, when the fastening element is positioned with its looking element overlying the cylinder shoulder, the cylinder is held firmly against displacement on the block. The block, in turn, holds the seal in place around the bowl neck by downward pressure exerted through the cylinder by the fastening element.

For a better understanding of the invention reference may be had to the accompanying drawing, in which:

Fig. 1 is a vertical sectional view of a centrifuge embodying the invention in a preferred form, and

Fig. 2 is a sectional view on the line 2-2 in Fig. 1.

For illustrative purposes, the invention will be described in connection with a centrifuge of the air-tight type commonly used for separating cream from milk. It will be understood, however, that the invention is not limited to centrifuges of this types, or to the separation of cream.

Referring to the drawing, the numeral IIl designates the centrifuge frame in which the centrifugal bowl is mounted for rotation. The bowl may be of any conventional form and therefore is not illustrated, except for the neck II having a vertical passage I la for discharging the cream from the separating chamber in the bowl. The neck I I is closely surrounded by two flexible seals I2 and I3 of annular form. A spacing member I4 is interposed between the seals and has radial passages I 4a through which any leakage between the bowl neck and the seals is led outwardly to an annular clearance space in the upper part of the frame and then discharged through an opening in the frame wall. The central part I2a of the lower seal extends downwardly along the bowl neck and through a central opening Illa in a horizontal internal flange Iilb on the frame. At its outer portion, the lower seal I2 is clamped between the flange Illb and the spacer Ill. The central portion I3a of the upper seal extends upwardly along the bowl neck, while the outer portion of this seal is seated on top of the spacer I4. At their intermediate portions, the seals are considerably thinner than their inner and outer portions, as shown at I2b and I31), respectively. By virtue of the relatively thin intermediate portions I21) and I32), the seals are better adapted to accommodate lateral movements of their inner portions incident to radial vibrations of the neck I I during rotation of the bowl.

A block l6 clamps the outer portion of the upper seal I3 against the spacer I4. The block it is located in a recess Ills in the top of the frame and forms a closure for the latter. Downward movement of the block into the recess Iilc, against the seal I3, is limited by a shoulder IBa engageable with the top of the frame. At its lower portion, the block is provided with a central recess Ilib forming a receiving chamber for the cream dischargedthrough the neck passage Ila. The outer wall of chamber I61) surrounds the outlet end of neck I I and the upper or inner portion of seal IS. The diameter of recess Ifib is approximately the maximum diameter of the thin portions I 2b and I3!) of the seals, so that a substantial clearance space is provided between the upper seal portion I30. and the side wall of the recess I512.

At its upper portion, the block I6 has an integral, horizontal internal flange I60 forming the upper wall of recess 5% and defining a central valve orifice Il directly overlying the outlet end of neck II. The orifice I'I afiords communication between the chamber or recess I52) and the interior of a hollow member I3 in the form of a vertical cylinder. The cylinder I8 is seated at its lower end on top of the block where it is held against lateral displacement by a rim IBd integral with the block. The cylinder I8 has a laterally extending duct 19 through which cream entering the cylinder may be discharged to a suitable pipe line connected to the duct.

The flow of cream through the orifice I1 is controlled by a disc valve 28 adapted to seat on top of flange Ific around the orifice so as to close it. As shown particularly in Fig. 2, the disc 28 is of polygonal shape, the corners forming projections Zlla engaging the inner wall of the cylinder. In this way, the projections 29a serve to guide the disc valve in its vertical movement, by sliding along the inner wall of the cylinder, while the spaces between the projections constitute passages through which the cream can flow upwardly into the cylinder when the disc valve is unseated. In its lower face, the disc valve is formed with a central recess Zilb of somewhat greater diameter than the orifice I? and having rounded edges.

A stem 2 I, which may be integral with the disc valve 29, extends upwardly through the cylinder I8 and is connected at its upper end to a flexible diaphragm 22. At its outer edge, the diaphragm 22 is clamped between the upper part of cylinder i8 and a housing 23, by means of a nut 24. A compression spring 25 in the housing 23 engages a pin 25 slidable in a central opening in a horizontal partition 23a in the housing. The pin 26 serves to transmit the downward thrust of spring 25 to the upper end of stem 2 I, so that the valve 2-53 imposes a yielding resistance to the flow of cream through orifice H. The compression of spring 25 may be adjustable by any suitable means (not shown) to vary the resistance imposed by the valve.

The cylinder I8 and the block I6 are held in assembled relation on the centrifuge frame by means of a fastening element 21 which, however, does not engage the block. At its lower end, the fastener 21 is threaded to the upper portion of frame I 0, as shown at 21a. From the threaded portion 21a, the fastener extends upwardly and inwardly so as to span the block I6, the upper edge of the fastener engaging the lower portion of lhe cylinder. At its upper edge, the fastener has a holding portion 21b engaging the top of a shoulder Ilia on the cylinder, the holding portion 21?) extending circumferentially around the cylinder over somewhat less than Diametrically opposite the holding portion 21b, the upper edge of the fastener has a locking portion 210 adapted to engage the top of shoulder I811. The shoulder I8a is formed with an interruption I8b forming a slot somewhat wider than the locking portion 270. The fastener 21 may be provided on its periphery with spaced projections 27d to facilitate rotation of the fastener, as will be described in greater detail presently.

The operation of the improved centrifuge is as follows: The cream discharging through neck I I into the receiving chamber IBb completely fills the chamber and acts to press the upper seal I3 against the spacer I4 and also against the bowl 51 neck, thereby making theseal more effective to prevent; leakage. chamber tab is. also. exerted against the. lower face: of valve 20. through the; valve orifice [1. When this pressure is. sufficient to; overcome the downward force. on the. valve, the latter is moved upwardly. from its seat. on the flange I60. Asa result, the. cream. flows upwardly through orifice IT and against the bottom of recess 2%, the cream then flowing outwardly between the flange 16c and the outer portion of the valve, and then upwardly into the cylinder through the spaces between the projections 20a. Because of the rounded edge of the recess 26b, a gradual reduction of pressure and velocity is effected, which is beneficial in avoiding impacts of the cream tending to break up the fat clusters and reduce the viscosity of the cream. It will be understood that the greater the pressure of the spring 25, the greater the resistance to fiow of cream and the more concentrated the cream. Also, any increase in the back pressure in the discharge line from duct l9 will cause an increased upward thrust on diaphragm 22, whereby the effect on disc valve 20 will be counteracted; and conversely, any decrease in the back pressure will reduce the pressure of the cream exerted upwardly against diaphrgam 22. Consequently, the flow resistance imposed upon the cream by valve 20 is maintained substantially constant, except for such desired changes as may be brought about by manual adjustment of the compression of spring 25. Thus, the concentration of the cream discharging through duct ill will be maintained substantially constant at all times for any given adjustment of spring 25, regardless of variations in the feed rate to the bowl or other factors tending to influence the concentration of the cream.

When it is desired to remove the cylinder [8, as for cleaning purposes, housing 23 is first removed by unscrewing nut 24, and any pipe connections are unscrewed from duct IS. The fastener 2'! is then unscrewed from the frame In at 27c, and the cylinder and the fastener 21 are lifted from the frame. In order to completely separate the cylinder Hi from the fastener 21, the fastener is rotated about the cylinder until locking portion 210 is aligned with the shoulder interruption 18?), as shown in Fig. 2. The cylinder is then tilted so as to raise the side having slot l8b, the opposite side being retained in the holding portion 21b of the fastener. When the cylinder is thus tilted sufficiently to raise its lower end above the level of the locking portion 210, it may be moved laterally to disengage shoulder I8a from beneath the holding portion 21b, so that the cylinder can be withdrawn from the fastener. It will be understood that when the cylinder is in position on the block, and the fastener 21 is entirely screwed down at threaded portion 21a, the extent of the circumferential holding portion 21b is sufficient to hold the cylinder securely on the block regardless of whether locking portion 27 is in or out of alignment with slot I 8b. In order to obtain access to the seals i2 and I3, the cylinder and fastener are removed from the frame as above described, whereupon block l6 may be lifted from recess H10 in the frame.

It will be evident that since block I 6 is not engaged by any fastening element, it is free to center itself with respect to the frame and the cylinder E3, to the extent permitted by the tolerances in the fits between the block and the frame and cylinder, respectively. Also, by providing the block itself with the valve orifice I! in the plane The pressure of the cream. in.

offia'nge l tic, the ever-all height of the; apparatus member communicating with said outlet through a valved orifice and having a discharge passage for said component, and a flexible seal surrounding the neck and secured to the frame to provide air-tight communication between said outlet and orifice, the improvement which comprises a block seated on the seal to hold the same in position around the neck, the block having in its lower face a recess forming a receiving chamber for the component passing through said outlet, a valve seat between said chamber and hollow member and forming said orifice, a valve in said hollow member coacting with the seat to impose a yielding resistance to flow through the orifice between said outlet and said discharge passage, and a fastening element surrounding but spaced from the block and removably secured at one end to the frame and engaged at its other end with the hollow member to hold said member, block and seal in assembled relation on the frame, said hollow member having an interrupted shoulder, and the fastening element having an interrupted edge portion overlying said shoulder, the hollow member and fastening element being rotatable relatively to permit withdrawal of the shoulder through the interruptions in said edge portion.

2. In a closed centrifuge having a frame, a centrifugal bowl neck rotatable in the frame and affording outlet at its upper end for a centrifugally separated component, a stationary hollow member communicating with said rotating outlet through a valved orifice and having a discharge passage for said component, and a flexible seal surrounding the neck and secured to the frame to provide air-tight communication between said outlet and orifice, the improvement which comprises a block seated on the seal to hold the same in position around the neck, the block having a recess in its lower portion forming a receiving chamber surrounding said outlet and adapted to receive the component passing therethrough, the walls of said receiving chamber extending inwardly above said outlet to form a top opening substantially smaller than the open bottom of the chamber and forming said orifice, a disc valve in said hollow member adapted to seat on the block to close the orifice and imposing a yielding resistance to fiow between the rotating outlet and the stationary discharge passage, guide means on the disc valve engageable with and vertically reciprocable on the inner wall of said hollow member to center the valve relative to the orifice, and a releasable fastening element spanning the block and threaded at its lower end on the frame, said hollow member having an interrupted shoulder underlying the upper edge of the fastening element, said upper edge having interruptions separating a. holding portion of the edge from a diametrically opposed locking portion, whereby upon rotation of the fastening element to align 7 said locking portion with the shoulder interruption, the hollow member can be tilted to enable its shoulder to be withdrawn laterally from beneath said holding portion. 7

JAMES EDWARD COOK.

REFERENCES CITED The following references are of record in the file of this patent:

Number 8 UNITED STATES PATENTS Name Date Cadman 1 Mar. 25, 1919 Lindgren May 28, 1935 Strezynski Dec. 3, 1935 Ha pgood May 30, 1939 Risberg Sept. 26, 1939 Bath Mar. 31, 1942 

